题干

夏夜,大批雄性萤火虫尾部的萤火一明一灭,它们这么做的目的是(  )

A:点缀夜空

B:进行求偶表演

C:引诱食物前来

D:散热

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答案(点此获取答案解析)

B

同类题4

请认真阅读下列短文,从短文后各题所给的A、B、C、D四个选项中,选出最佳选项。

C

    If you want to disturb the car industry, you'd better have a few billion dollars: Mom-and-pop carmakers are unlikely to beat the biggest car companies. But in agriculture, small farmers can get the best of the major players. By connecting directly with customers, and by responding quickly to changes in the markets as well as in the ecosystems(生态系统), small farmers can keep one step ahead of the big guys. As the co-founder of the National Young Farmers Coalition (NYFC, 美国青年农会)and a family farmer myself. I have a front-row seat to the innovations among small farmers that are transforming the industry.

    For example, take the Quick Cut Greens Harvester, a tool developed just a couple of years ago by a young farmer, Jonathan Dysinger, in Tennessee, with a small loan from a local Slow Money group. It enables small-scale farmers to harvest 175 pounds of green vegetables per hour—a huge improvement over harvesting just a few dozen pounds by hand—suddenly making it possible for the little guys to compete with large farms of California. Before the tool came out, small farmers couldn't touch the price per pound offered by California farms. But now, with the combination of a better price point and a generally fresher product, they can stay in business.

    The sustainable success of small farmers, though, won't happen without fundamental changes to the industry. One crucial factor is secure access to land. Competition from investors, developers, and established large farmers makes owning one's own land unattainable for many new farmers. From 2004 to 2013, agricultural land values doubled, and they continue to rise in many regions.

    Another challenge for more than a million of the most qualified farm workers and managers is a non-existent path to citizenship — the greatest barrier to building a farm of their own. With farmers over the age of 65 outnumbering(多于)farmers younger than 35 by six to one, and with two-thirds of the nation's farmland in need of a new farmer, we must clear the path for talented people willing to grow the nation's food.

    There are solutions that could light a path toward a more sustainable and fair farm economy, but farmers can't clumsily put them together before us. We at the NYFC need broad support as we urge Congress to increase farmland conservation, as we push for immigration reform, and as we seek policies that will ensure the success of a diverse and ambitious next generation of farms from all backgrounds. With a new farm bill to be debated in Congress, consumers must take a stand with young farmers.

同类题5

根据短文理解,选择正确答案。

    When I was about 12, I had an enemy, a girl who liked to point out my shortcomings(缺点). Week by week her list grew: I was very thin, I wasn't a good student,I talked too much, I was too proud, and so on. I tried to hear all this as long as  could. At last, I became very angry. I ran to my father with tears in my eyes.

    He listened to me quietly, then he asked. “Are the things she says true or not? Janet, didn't you ever wonder what you're really like? Well, you now have that girl's opinion. Go and make a list of everything she said and mark the points that are true. Pay no attention to the other things she said.”I did as he told me. To my great surprise, I discovered that about half the things were true. Some of them I couldn't change (like being very thin), but a good number I could—and suddenly I wanted to change. For the first time I go to fairly clear picture of myself.

    I brought the list back to Daddy. He refused to take it. “That's just for you,” he said. “You know better than anyone else the truth about yourself. But you have to learn to listen, not just close your ears in anger and feeling hurt. When some thing said about you is true, you'll find it will be of help to you. Our world is full of people who think they know your duty. Don't shut your ears. Listen to them all, but hear the truth and do what you know is the right thing to do.” Daddy's advice has returned to me at many important moments. In my life, I've never had a better piece of advice.